The described invention relates in general to two and three dimensional biocompatible structures that further include scaffolds of micro-scale or nano-scale fibers or combinations thereof, and more specifically a synthetic organ, such as a trachea, manufactured from such fibers.
In mammalian anatomy, the trachea (or windpipe) is a tube that connects the pharynx or larynx to the lungs, thereby allowing the passage of air between these structures (see FIG. 1). The trachea is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus. This mucus lines the cells of the trachea to trap inhaled foreign particles that the cilia then direct upward toward the larynx and then the pharynx where it can be either swallowed into the stomach or expelled as phlegm. The trachea typically has an inner diameter of about 25.4 millimeters (1.00 in) and a length of about 10 to 16 centimeters (3.9 to 6.3 inches). It begins at the lower border of the larynx, level with the sixth cervical vertebra, and bifurcates into the primary bronchi at the vertebral level of thoracic vertebra T5, or up to two vertebrae lower or higher, depending on breathing.
Fifteen to twenty incomplete C-shaped cartilaginous rings reinforce the anterior and lateral sides of the trachea to protect and maintain the airway, leaving a membranous wall dorsally without cartilage. The trachealis muscle connects the ends of the incomplete rings and contracts during coughing, reducing the size of the lumen of the trachea to increase the air flow rate. The esophagus lies posteriorly to the trachea. The cartilaginous rings are incomplete to allow the trachea to collapse slightly so that food can pass down the esophagus. A flap-like epiglottis closes the opening to the larynx during swallowing to prevent swallowed matter from entering the trachea.
A number of diseases and conditions are known to affect the trachea including, for example, choking, tracheotomy (a surgical procedure on the neck to open a direct airway through an incision in the trachea), tracheomalacia (weakening of the tracheal cartilage), tracheal collapse (in certain animals such as dogs), tracheobronchial injury (perforation of the trachea or bronchi), and Mounier-Kuhn syndrome (which causes abnormal enlargement of the trachea). Partial or complete loss of the trachea due to cancer or other diseases can have a catastrophic, if not fatal, effect on an animal or human.
A number of in vivo prostheses for luminal structures such as the trachea are known in the art. Typically these prostheses are formed by donor structures from cadavers or are manmade structures. However, these existing structures are subject to failure due to anastomotic stenosis, luminal stenosis, infection, dislocation, and migration, among other causes. Therefore, there is an ongoing need for artificial or prosthetic versions of organs such as the trachea that will provide the patient, human or otherwise, with a functioning replacement for the lost, damaged, or diseased organ.